Demos/Device/LowLevel/USBtoSerial/USBtoSerial.c

   1 /*
   2              LUFA Library
   3      Copyright (C) Dean Camera, 2009.
   4
   5   dean [at] fourwalledcubicle [dot] com
   6       www.fourwalledcubicle.com
   7 */
   8
   9 /*
  10   Copyright 2009  Dean Camera (dean [at] fourwalledcubicle [dot] com)
  11
  12   Permission to use, copy, modify, and distribute this software
  13   and its documentation for any purpose and without fee is hereby
  14   granted, provided that the above copyright notice appear in all
  15   copies and that both that the copyright notice and this
  16   permission notice and warranty disclaimer appear in supporting
  17   documentation, and that the name of the author not be used in
  18   advertising or publicity pertaining to distribution of the
  19   software without specific, written prior permission.
  20
  21   The author disclaim all warranties with regard to this
  22   software, including all implied warranties of merchantability
  23   and fitness.  In no event shall the author be liable for any
  24   special, indirect or consequential damages or any damages
  25   whatsoever resulting from loss of use, data or profits, whether
  26   in an action of contract, negligence or other tortious action,
  27   arising out of or in connection with the use or performance of
  28   this software.
  29 */
  30
  31 #include "USBtoSerial.h"
  32
  33 /* Globals: */
  34 /** Contains the current baud rate and other settings of the virtual serial port.
  35  *
  36  *  These values are set by the host via a class-specific request, and the physical USART should be reconfigured to match the
  37  *  new settings each time they are changed by the host.
  38  */
  39 CDC_Line_Coding_t LineCoding = { .BaudRateBPS = 9600,
  40                                  .CharFormat  = OneStopBit,
  41                                  .ParityType  = Parity_None,
  42                                  .DataBits    = 8            };
  43
  44 /** Ring (circular) buffer to hold the RX data - data from the host to the attached device on the serial port. */
  45 RingBuff_t Rx_Buffer;
  46
  47 /** Ring (circular) buffer to hold the TX data - data from the attached device on the serial port to the host. */
  48 RingBuff_t Tx_Buffer;
  49
  50 /** Flag to indicate if the USART is currently transmitting data from the Rx_Buffer circular buffer. */
  51 volatile bool Transmitting = false;
  52
  53 /** Main program entry point. This routine configures the hardware required by the application, then
  54  *  starts the scheduler to run the application tasks.
  55  */
  56 int main(void)
  57 {
  58         SetupHardware();
  59
  60         /* Ring buffer Initialization */
  61         Buffer_Initialize(&Rx_Buffer);
  62         Buffer_Initialize(&Tx_Buffer);
  63
  64         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
  65
  66         for (;;)
  67         {
  68                 CDC_Task();
  69                 USB_USBTask();
  70         }
  71 }
  72
  73 /** Configures the board hardware and chip peripherals for the demo's functionality. */
  74 void SetupHardware(void)
  75 {
  76         /* Disable watchdog if enabled by bootloader/fuses */
  77         MCUSR &= ~(1 << WDRF);
  78         wdt_disable();
  79
  80         /* Disable clock division */
  81         clock_prescale_set(clock_div_1);
  82
  83         /* Hardware Initialization */
  84         LEDs_Init();
  85         ReconfigureUSART();
  86         USB_Init();
  87 }
  88
  89 /** Event handler for the USB_Connect event. This indicates that the device is enumerating via the status LEDs and
  90  *  starts the library USB task to begin the enumeration and USB management process.
  91  */
  92 void EVENT_USB_Connect(void)
  93 {
  94         /* Indicate USB enumerating */
  95         LEDs_SetAllLEDs(LEDMASK_USB_ENUMERATING);
  96 }
  97
  98 /** Event handler for the USB_Disconnect event. This indicates that the device is no longer connected to a host via
  99  *  the status LEDs and stops the USB management and CDC management tasks.
 100  */
 101 void EVENT_USB_Disconnect(void)
 102 {
 103         /* Reset Tx and Rx buffers, device disconnected */
 104         Buffer_Initialize(&Rx_Buffer);
 105         Buffer_Initialize(&Tx_Buffer);
 106
 107         /* Indicate USB not ready */
 108         LEDs_SetAllLEDs(LEDMASK_USB_NOTREADY);
 109 }
 110
 111 /** Event handler for the USB_ConfigurationChanged event. This is fired when the host set the current configuration
 112  *  of the USB device after enumeration - the device endpoints are configured and the CDC management task started.
 113  */
 114 void EVENT_USB_ConfigurationChanged(void)
 115 {
 116         /* Setup CDC Notification, Rx and Tx Endpoints */
 117         Endpoint_ConfigureEndpoint(CDC_NOTIFICATION_EPNUM, EP_TYPE_INTERRUPT,
 118                                        ENDPOINT_DIR_IN, CDC_NOTIFICATION_EPSIZE,
 119                                    ENDPOINT_BANK_SINGLE);
 120
 121         Endpoint_ConfigureEndpoint(CDC_TX_EPNUM, EP_TYPE_BULK,
 122                                        ENDPOINT_DIR_IN, CDC_TXRX_EPSIZE,
 123                                    ENDPOINT_BANK_SINGLE);
 124
 125         Endpoint_ConfigureEndpoint(CDC_RX_EPNUM, EP_TYPE_BULK,
 126                                        ENDPOINT_DIR_OUT, CDC_TXRX_EPSIZE,
 127                                    ENDPOINT_BANK_SINGLE);
 128
 129         /* Indicate USB connected and ready */
 130         LEDs_SetAllLEDs(LEDMASK_USB_READY);
 131 }
 132
 133 /** Event handler for the USB_UnhandledControlPacket event. This is used to catch standard and class specific
 134  *  control requests that are not handled internally by the USB library (including the CDC control commands,
 135  *  which are all issued via the control endpoint), so that they can be handled appropriately for the application.
 136  */
 137 void EVENT_USB_UnhandledControlPacket(void)
 138 {
 139         uint8_t* LineCodingData = (uint8_t*)&LineCoding;
 140
 141         /* Process CDC specific control requests */
 142         switch (USB_ControlRequest.bRequest)
 143         {
 144                 case REQ_GetLineEncoding:
 145                         if (USB_ControlRequest.bmRequestType == (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE))
 146                         {
 147                                 /* Acknowledge the SETUP packet, ready for data transfer */
 148                                 Endpoint_ClearSETUP();
 149
 150                                 /* Write the line coding data to the control endpoint */
 151                                 Endpoint_Write_Control_Stream_LE(LineCodingData, sizeof(LineCoding));
 152
 153                                 /* Finalize the stream transfer to send the last packet or clear the host abort */
 154                                 Endpoint_ClearOUT();
 155                         }
 156
 157                         break;
 158                 case REQ_SetLineEncoding:
 159                         if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
 160                         {
 161                                 /* Acknowledge the SETUP packet, ready for data transfer */
 162                                 Endpoint_ClearSETUP();
 163
 164                                 /* Read the line coding data in from the host into the global struct */
 165                                 Endpoint_Read_Control_Stream_LE(LineCodingData, sizeof(LineCoding));
 166
 167                                 /* Finalize the stream transfer to clear the last packet from the host */
 168                                 Endpoint_ClearIN();
 169
 170                                 /* Reconfigure the USART with the new settings */
 171                                 ReconfigureUSART();
 172                         }
 173
 174                         break;
 175                 case REQ_SetControlLineState:
 176                         if (USB_ControlRequest.bmRequestType == (REQDIR_HOSTTODEVICE | REQTYPE_CLASS | REQREC_INTERFACE))
 177                         {
 178                                 /* Acknowledge the SETUP packet, ready for data transfer */
 179                                 Endpoint_ClearSETUP();
 180
 181                                 /* NOTE: Here you can read in the line state mask from the host, to get the current state of the output handshake
 182                                          lines. The mask is read in from the wValue parameter in USB_ControlRequest, and can be masked against the
 183                                                  CONTROL_LINE_OUT_* masks to determine the RTS and DTR line states using the following code:
 184                                 */
 185
 186                                 /* Acknowledge status stage */
 187                                 while (!(Endpoint_IsINReady()));
 188                                 Endpoint_ClearIN();
 189                         }
 190
 191                         break;
 192         }
 193 }
 194
 195 /** Task to manage CDC data transmission and reception to and from the host, from and to the physical USART. */
 196 void CDC_Task(void)
 197 {
 198         if (USB_IsConnected)
 199         {
 200 #if 0
 201                 /* NOTE: Here you can use the notification endpoint to send back line state changes to the host, for the special RS-232
 202                                  handshake signal lines (and some error states), via the CONTROL_LINE_IN_* masks and the following code:
 203                 */
 204
 205                 USB_Notification_Header_t Notification = (USB_Notification_Header_t)
 206                         {
 207                                 .NotificationType = (REQDIR_DEVICETOHOST | REQTYPE_CLASS | REQREC_INTERFACE),
 208                                 .Notification     = NOTIF_SerialState,
 209                                 .wValue           = 0,
 210                                 .wIndex           = 0,
 211                                 .wLength          = sizeof(uint16_t),
 212                         };
 213
 214                 uint16_t LineStateMask;
 215
 216                 // Set LineStateMask here to a mask of CONTROL_LINE_IN_* masks to set the input handshake line states to send to the host
 217
 218                 Endpoint_SelectEndpoint(CDC_NOTIFICATION_EPNUM);
 219                 Endpoint_Write_Stream_LE(&Notification, sizeof(Notification));
 220                 Endpoint_Write_Stream_LE(&LineStateMask, sizeof(LineStateMask));
 221                 Endpoint_ClearIN();
 222 #endif
 223
 224                 /* Select the Serial Rx Endpoint */
 225                 Endpoint_SelectEndpoint(CDC_RX_EPNUM);
 226
 227                 /* Check to see if a packet has been received from the host */
 228                 if (Endpoint_IsOUTReceived())
 229                 {
 230                         /* Read the bytes in from the endpoint into the buffer while space is available */
 231                         while (Endpoint_BytesInEndpoint() && (BUFF_STATICSIZE - Rx_Buffer.Elements))
 232                         {
 233                                 /* Store each character from the endpoint */
 234                                 Buffer_StoreElement(&Rx_Buffer, Endpoint_Read_Byte());
 235                         }
 236
 237                         /* Check to see if all bytes in the current packet have been read */
 238                         if (!(Endpoint_BytesInEndpoint()))
 239                         {
 240                                 /* Clear the endpoint buffer */
 241                                 Endpoint_ClearOUT();
 242                         }
 243                 }
 244
 245                 /* Check if Rx buffer contains data - if so, send it */
 246                 if (Rx_Buffer.Elements)
 247                   Serial_TxByte(Buffer_GetElement(&Rx_Buffer));
 248
 249                 /* Select the Serial Tx Endpoint */
 250                 Endpoint_SelectEndpoint(CDC_TX_EPNUM);
 251
 252                 /* Check if the Tx buffer contains anything to be sent to the host */
 253                 if (Tx_Buffer.Elements)
 254                 {
 255                         /* Wait until Serial Tx Endpoint Ready for Read/Write */
 256                         while (!(Endpoint_IsReadWriteAllowed()));
 257
 258                         /* Write the bytes from the buffer to the endpoint while space is available */
 259                         while (Tx_Buffer.Elements && (Endpoint_BytesInEndpoint() < CDC_TXRX_EPSIZE))
 260                         {
 261                                 /* Write each byte retreived from the buffer to the endpoint */
 262                                 Endpoint_Write_Byte(Buffer_GetElement(&Tx_Buffer));
 263                         }
 264
 265                         /* Remember if the packet to send completely fills the endpoint */
 266                         bool IsFull = (Endpoint_BytesInEndpoint() == CDC_TXRX_EPSIZE);
 267
 268                         /* Send the data */
 269                         Endpoint_ClearIN();
 270
 271                         /* If no more data to send and the last packet filled the endpoint, send an empty packet to release
 272                          * the buffer on the receiver (otherwise all data will be cached until a non-full packet is received) */
 273                         if (IsFull && !(Tx_Buffer.Elements))
 274                         {
 275                                 /* Wait until Serial Tx Endpoint Ready for Read/Write */
 276                                 while (!(Endpoint_IsReadWriteAllowed()));
 277
 278                                 /* Send an empty packet to terminate the transfer */
 279                                 Endpoint_ClearIN();
 280                         }
 281                 }
 282         }
 283 }
 284
 285 /** ISR to handle the USART receive complete interrupt, fired each time the USART has received a character. This stores the received
 286  *  character into the Tx_Buffer circular buffer for later transmission to the host.
 287  */
 288 ISR(USART1_RX_vect, ISR_BLOCK)
 289 {
 290         /* Only store received characters if the USB interface is connected */
 291         if (USB_IsConnected)
 292         {
 293                 /* Character received, store it into the buffer */
 294                 Buffer_StoreElement(&Tx_Buffer, UDR1);
 295         }
 296 }
 297
 298 /** Reconfigures the USART to match the current serial port settings issued by the host as closely as possible. */
 299 void ReconfigureUSART(void)
 300 {
 301         uint8_t ConfigMask = 0;
 302
 303         /* Determine parity - non odd/even parity mode defaults to no parity */
 304         if (LineCoding.ParityType == Parity_Odd)
 305           ConfigMask = ((1 << UPM11) | (1 << UPM10));
 306         else if (LineCoding.ParityType == Parity_Even)
 307           ConfigMask = (1 << UPM11);
 308
 309         /* Determine stop bits - 1.5 stop bits is set as 1 stop bit due to hardware limitations */
 310         if (LineCoding.CharFormat == TwoStopBits)
 311           ConfigMask |= (1 << USBS1);
 312
 313         /* Determine data size - 5, 6, 7, or 8 bits are supported */
 314         if (LineCoding.DataBits == 6)
 315           ConfigMask |= (1 << UCSZ10);
 316         else if (LineCoding.DataBits == 7)
 317           ConfigMask |= (1 << UCSZ11);
 318         else if (LineCoding.DataBits == 8)
 319           ConfigMask |= ((1 << UCSZ11) | (1 << UCSZ10));
 320
 321         /* Enable double speed, gives better error percentages at 8MHz */
 322         UCSR1A = (1 << U2X1);
 323
 324         /* Enable transmit and receive modules and interrupts */
 325         UCSR1B = ((1 << RXCIE1) | (1 << TXEN1) | (1 << RXEN1));
 326
 327         /* Set the USART mode to the mask generated by the Line Coding options */
 328         UCSR1C = ConfigMask;
 329
 330         /* Set the USART baud rate register to the desired baud rate value */
 331         UBRR1  = SERIAL_2X_UBBRVAL((uint16_t)LineCoding.BaudRateBPS);
 332 }